Counties in California that have enacted “GMO-free” growing zones now total nearly 14,000 square miles out of about 67,000 square miles devoted to farming in the state. The bans on GMO farming in the zones, which are appearing across the U.S. on a county by county basis, are backed by organic dairies, natural food co-ops and heirloom seed companies. The latest ban, opposed by the local farm bureau, came in a ballot measure in the November election in Sonoma County, Calif. The bureau said the measure was vaguely worded and would bar farmers from using any appropriate technology to fight pests and disease.